ep42 - inControl guide to ... the Nyquist criterion

Outline00:00 – Intro04:43 – Life and background08:45 – Bell Labs13:42 – Inventing the negative feedback amplifier18:15 – Nyquist's landmark contributions20:43 – Regeneration theory27:10 – Frequency response32:03 – Cauchy’s argument principle36:05 – The Nyquist criterion41:37 – Why is it so hard?45:27 – Robustness, margins, and practical aspects56:41 – Beyond the Nyquist criterion1:04:25 – Pitfalls and common misunderstandings1:07:00 – OutroLinksBrian Douglas's video: http://y2u.be/sof3meN96MAThe Idea Factory: https://en.wikipedia.org/wiki/The_Idea_FactoryInventing the Negative Feedback Amplifier: https://doi.org/10.1109/MSPEC.1977.6501721Johnson–Nyquist noise:  https://doi.org/10.1103/PhysRev.32.110Nyquist sampling theorem: https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theoremRegeneration theory: https://doi.org/10.1002/j.1538-7305.1932.tb02344.xGain and phase margins: https://en.wikipedia.org/wiki/Bode_plot#Gain_margin_and_phase_marginRouth–Hurwitz criterion: https://en.wikipedia.org/wiki/Routh%E2%80%93Hurwitz_stability_criterionÅström’s lecture: https://archive.control.lth.se/media/Staff/KarlJohanAstrom/Lectures/ASMENyquistLecture2005.pdfScale-Relative Graphs: https://doi.org/10.1109/TAC.2023.3234016Support the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 - Intro02:55 - Brachistochrone problem20:52 - Beginning of the calculus of variations32:00 - Principle of least action42:37 - Maximum principle1:02:35 - Dynamic programming1:11:12 - Linear quadratic control1:16:37 - Beyond optimal control: games, nonsmooth analysis, MPC, RL1:28:40 - OutroLinks300 years of optimal control: https://tinyurl.com/2s3t8se4Brachistochrone: https://tinyurl.com/mwmv38ewActa Eruditorum, 1696: https://tinyurl.com/55yf5v49Acta Eruditorum, 1697: https://tinyurl.com/2a7msaajBernoulli family: https://tinyurl.com/y2vx2xdnLeibniz–Newton calculus controversy: https://tinyurl.com/3974fdhdCalculus of variations: https://tinyurl.com/3vvz8tufBeginning of the Calculus of Variations: https://tinyurl.com/mv6btxfnLagrangian mechanics: https://tinyurl.com/ycx5fv46Euler–Lagrange equation: https://tinyurl.com/53yybvyxHamiltonian mechanics: https://tinyurl.com/yfrd8zhzHamilton–Jacobi equation: https://tinyurl.com/46m9cuvsPontryagin: https://tinyurl.com/35ehxnexPontryagin’s autobiography:  https://ega-math.narod.ru/LSP/book.htmDiscovery of the Maximum Principle: https://tinyurl.com/3s43nv4tMaximum Principle: https://tinyurl.com/4f7352t4Goddard problem: https://tinyurl.com/5n8swp2mHamilton–Jacobi–Bellman equation: https://tinyurl.com/4uemn5y4Kalman filter: https://tinyurl.com/39zx5yryClarke: https://tinyurl.com/yj2tzcjbMPC: https://tinyurl.com/4sf5pzvy RL: https://tinyurl.com/ee5ne7szAlphaGo: https://tinyurl.com/ydrf8jscSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 - Intro03:18 - Early days: why control, M. Athans, and IDSS12:21 - What is gain scheduling?33:37 - Paradigm shifts & the ‘90s: Minnesota → Texas → LA 42:19 - Robustness & fundamental limitations of nonlinear systems57:35 - Set-valued control & estimation01:04:52 - Game theory & multi-agent control 01:28:18 - Learning & dissipativity in games & multi agent AI01:45:03 - KAUST: building something new01:53:33 - On human-algorithmic interaction01:59:07 - Advice to future students: control, jiu-jitsu, and chatbots in education2:10:02 - OutroLinksJeff’s website: https://tinyurl.com/52btmmz7CSM interview: https://tinyurl.com/49wh98x7Domain: feedbackcontrol.comM. Athans: https://tinyurl.com/nhbw66waPhD thesis: https://tinyurl.com/5eyxkfm6IDSS: https://tinyurl.com/bdenwy6dResearch on gain scheduling: https://tinyurl.com/55se8zcr Overview of LPV systems: https://tinyurl.com/3ksff58b Åström’s lecture: https://tinyurl.com/33mxkkfe Necessity of the small gain theorem: https://tinyurl.com/mjn9eeb4 Sensitivity reduction for nonlinear plants: https://tinyurl.com/23tej5ypRespect the unstable: https://tinyurl.com/3yww5eds Differential inclusion: https://tinyurl.com/4yvc8vccLectures on game theory: https://tinyurl.com/4z8hh3rnDynamic fictitious play: https://tinyurl.com/yc6wsxjjCooperative control and potential games: https://tinyurl.com/4hbmrt72Dissipativity theory in game theory: https://tinyurl.com/3theyc7xPopulation games, stable games, and passivity: https://tinyurl.com/zxwtzv6wGame theory and control: https://tinyurl.com/yencrwm3Higher-order uncoupled learning: https://tinyurl.com/37Support the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 - Intro05:01 - Female Influencers in Control — The Backstory08:08 - Sofya Kovalevskaya15:21 - Irmgard Lotz26:16 - A new wave of control influencers34:26 - Some data43:38 - What can one do? 1:00:10 - Exhibition + survey1:05:21 - OutroLinksFemale influencers in control project: https://tinyurl.com/mv879ahfCharlotta Johnsson: https://tinyurl.com/343esbeuEva Westin: https://tinyurl.com/3p6fd5n8Margret Bauer: https://tinyurl.com/47d35xzbSofya Kovalevskaya: https://tinyurl.com/4mmzruwcRemembering Sofya Kovalevskaya: https://tinyurl.com/4cpw7vffIrmgard Lotz: https://tinyurl.com/y2exmndmFlow Computation Pioneer Irmgard Flügge-Lotz (1903–1974): https://tinyurl.com/4cy3xsp3Discontinuous Automatic Control: https://tinyurl.com/yeys5dxxHistorical Female Influencers in Automatic Control: https://tinyurl.com/yxw4bjxeActivity report: https://tinyurl.com/jwzn4z3cSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 – Intro07:22 – Anatomy of a feedback loop15:12 – A brief historical recap on the history of feedback23:40 – Inventing the negative feedback amplifier34:28 – Feedback in biology, economics, society, and ... board games!52:44 – Negative vs positive feedback59:15 – Feedback, causality, and the arrow of time1:06:22 – Classics: fundamental limitations, uncertainty, robustness1:21:30 – Adaptive control: learning in the loop1:29:50 – Modern AI feedback loops (RL, social media, alignment)1:40:40 – OutroLinksWatt’s flyball governor: https://tinyurl.com/ne5nene3Maxwell - "On Governors": https://tinyurl.com/2a7cxj7m Black - "Inventing the negative-feedback amplifier": https://tinyurl.com/yevsemdpNyquist Criterion: https://tinyurl.com/33hfbw8mBode's integral: https://tinyurl.com/53sxkdzuWiener - "Cybernetics": https://tinyurl.com/yta899ayApoptosis: https://tinyurl.com/mcxjycka Predator–prey dynamics (Lotka–Volterra): https://tinyurl.com/5cvx33tn Bird migration cues (photoperiodism): https://tinyurl.com/y2e7t22v Neuron action potentials: https://tinyurl.com/2wemwdn4Economic equilibrium & feedback: https://tinyurl.com/nhdx7r3sEcho chambers: https://tinyurl.com/4v8yk7e8 Game design: https://tinyurl.com/bdhdhv38Gap metric (Vinnicombe): https://tinyurl.com/y9nw3yveGeorgiou, Smith - "Feedback Control and the Arrow of Time": https://tinyurl.com/5xvj76jrAnnaswamy, Fradkov - "A Historical Perspective of Adaptive Control and Learning": https://tinyurl.com/4nfew8vm Algorithmic trading flash crash (2010): https://tinyurl.com/2dsrs8j2AI alignment: https://tinyurl.com/yvs3wnj8Support the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline 00:00 - Intro 03:12 - Early life 09:07 - St. Petersburg: Stability of Ellipsoidal Bodies 20:13 - Kharkov: The General Problem of the Stability of Motion 34:37 - Back to St. Petersburg: Probability & Academy 46:22 - Tragic end 49:50 - Posthumous recognition  57:49 - Legacy 1:20:39 - OutroLinksA. M. Lyapunov: https://tinyurl.com/3kjuhfnsS. Lyapunov: https://tinyurl.com/mury7p3sSmirnov's bio: https://tinyurl.com/6wpffh3zBissell's essay: https://tinyurl.com/3ds3hubjSechenov: https://tinyurl.com/ypsr37vc Krylov: https://tinyurl.com/44wez8w5Krylov subspace: https://tinyurl.com/bw527uh2Chebyshev: https://tinyurl.com/2n35usfrThe General Problem of Stability of Motion: https://tinyurl.com/mv2jchv2Lyapunov stability: https://tinyurl.com/bb59vcufCentral limit theorem: https://tinyurl.com/3r36p458Van der Pol oscillator: https://tinyurl.com/3s68yyhrMassera’s theorem: https://tinyurl.com/2zjmtvjwLaSalle’s invariance principle: https://tinyurl.com/pjnrp3fhKrasovskii: https://tinyurl.com/junbujswPopov criterion: https://tinyurl.com/uyt3kx5bControl Lyapunov function: https://tinyurl.com/3v7bnusjArtstein–Sontag formula: https://tinyurl.com/3fdebmm3Input-to-state stability: https://tinyurl.com/3nca9nj6Lyapunov equation: https://tinyurl.com/mvakw3ywHybrid systems: https://tinyurl.com/v39up6wkControl barrier function: https://tinyurl.com/sy4p5jjDominance theory: https://tinyurl.com/msvnd4dvSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 – Intro00:51 – Early steps in research09:55 – Historical overview of traffic control25:20 – What is traffic?34:06 – Road traffic control45:37 – PI control of road junctions58:19 – From macroscopic to microscopic simulations and back1:10:08 – Dynamic traffic assignment1:21:28 – Return to Greece1:28:33 – The optimal control problem1:41:48 – Traffic estimation1:47:34 – The impact of automation and connectivity1:59:20 – Traffic as an artificial fluid2:07:51 – The future of traffic control2:10:48 – Advice to future students2:13:53 – OutroLinkHomepage: https://tinyurl.com/yw7kee97CSS day lecture: https://tinyurl.com/46vua4r7Monograph - Applications of Automatic Control Concepts to Traffic Flow Modeling and Control: https://tinyurl.com/5czax788Review of road traffic control strategies: https://tinyurl.com/48u235pwALINEA: https://tinyurl.com/bdtvny87METANET: https://tinyurl.com/3h9xv48tAIMSUM:https://tinyurl.com/mr2xkryjAMOC: https://tinyurl.com/3v2xysr2HERO: https://tinyurl.com/yzn6vkwhReal-time freeway traffic state estimation based on extended Kalman filter: a general approach: https://tinyurl.com/2ubsh7cyTRAMAN: https://tinyurl.com/ypr65cfaCoordinated and integrated control of motorway networks via non-linear optimal control: https://tinyurl.com/3v2xysr2Motorway traffic flow modelling, estimation and control with vehicle automation and communication systems: https://tinyurl.com/49679hy8From road congestion to vehicle-control enabled artificial traffic fluids: https://tinyurl.com/pk4j8htpSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline 00:00 – Intro 01:19 – Early steps: PhD journey & robotic hands 15:42 – What is a soft robot?23:35 – MIT years & models of soft robots 30:01 – Discretization & underactuation 37:21 – The regulation problem 47:01 – Pros and cons of soft robots 51:42 – The soft inverted pendulum 1:05:27 – Eigenmanifolds 1:15:22 – Physical intelligence 1:26:09 – On machine learning 1:37:49 – Embodied AI & TC on Robot Control 1:44:50 – Advice to future studentsLinks- Cosimo’s website: https://tinyurl.com/mt37597k- Piaggio Center: https://tinyurl.com/muryjw5h- Pisa Robotic Hand: https://tinyurl.com/4ujtec59- Model-Based Dynamic Controller for a Planar Soft Robot: https://tinyurl.com/5a8fv3c8 - Soft Robot definition (Encyclopaedia of Robotics): https://tinyurl.com/3y2jz987 - Isidori’s book: https://tinyurl.com/42254hav- CSM magazine paper: https://tinyurl.com/bd54an6x- Cosserat rod theory: https://tinyurl.com/zu73nadx - Strain function: https://tinyurl.com/y8v63ue2- Zero dynamics: https://tinyurl.com/2ezarn5e- The soft inverted pendulum: https://tinyurl.com/y4bzkkup- Templates and anchors: https://tinyurl.com/2957w6sz- Exciting Efficient Oscillations Through Eigenmanifold Stabilisation: https://tinyurl.com/yc3586y5- When Do Lyapunov Subcentre Manifolds Become Eigenmanifolds?: https://tinyurl.com/5tckw7xe- Passive walker: https://tinyurl.com/yjwwapv5- Strandbeests: https://tinyurl.com/494mfccu - Physical control: https://tinyurl.com/bdddb6ur- Morphological computation: https://tinyurl.com/an6vaahx- The Playful Machine: https://tinyurl.com/5525xys2Support the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 - Intro01:06 - The big idea03:42 - Controllability, observability, and  ... the space race!14:52 - Kálmán and the state-space paradigm00:00 - The math and intuition: state-space basics, definitions, and duality00:00 - A touch of nonlinearity00:00 - Developments in the field: a chronological tour00:00 - Controllability and observability: quo vaditis?00:00 - OutroLinksKálmán: https://tinyurl.com/bdzj7mtrControllability: https://tinyurl.com/28s5zxpnObservability: https://tinyurl.com/yjxncxdnPaper - "Contributions to the theory of optimal control": https://tinyurl.com/9wwf8pvhPaper - "Discovery and Invention": https://tinyurl.com/ryfn463nKálmán's speech -  Kyoto Prize : https://tinyurl.com/2ahrjdahPaper - Controllability of complex networks: https://tinyurl.com/3zk99n4sSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.

Outline00:00 - Intro00:42 - “Research should be fun”02:02 - Early steps in research09:00 - Book writing and meeting C. Desoer18:33 - Control synthesis via the factorization approach25:46 - The graph metric 29:27 - Robotics and CAIR36:00 - Randomized algorithms40:41 - On learning44:05 - Neural networks48:40 - Tata, hidden Markov models, and large deviations theory55:48 - Picking problems and role of luck58:07 - Compressed sensing and non-convex optimization01:02:17 - Interplay between control and machine learning01:09:10 - Advice to future students01:13:29 - Future of controlLinksSagar’s website: https://tinyurl.com/4hwruajsHilbert: https://tinyurl.com/ykpdh929Feedback Systems: https://tinyurl.com/2k3jsdatHow to Write Mathematics: https://tinyurl.com/35794bv9Nonlinear systems: https://tinyurl.com/2fdtnjcmC. Desoer: https://tinyurl.com/svhknrenControl Systems Synthesis — A Factorization Approach: https://tinyurl.com/59wdc4svAryabhata: https://tinyurl.com/43x6hfhpA Brief History of the Graph Topology: https://tinyurl.com/49uftzdkRobot Dynamics and Control: https://tinyurl.com/5b4cmt7mCAIR: https://tinyurl.com/rajdtxaxRandomized algorithms for robust controller synthesis using statistical learning theory: https://tinyurl.com/wanpyeucR. Tempo: https://tinyurl.com/jkufdwarVC dimension: https://tinyurl.com/mvwk8afmLearning and Generalisation: https://tinyurl.com/2s3mzh8hAre Analog Neural Networks Better Than Binary Neural Networks? https://tinyurl.com/3fnk27xcHidden Markov Processes: https://tinyurl.com/t5frrvfzAn Introduction to Compressed Sensing: https://tinyurl.com/fc6a8eerSupport the showPodcast infoPodcast website: https://www.incontrolpodcast.com/Apple Podcasts: https://tinyurl.com/5n84j85jSpotify: https://tinyurl.com/4rwztj3cRSS: https://tinyurl.com/yc2fcv4yYoutube: https://tinyurl.com/bdbvhsj6Facebook: https://tinyurl.com/3z24yr43Twitter: https://twitter.com/IncontrolPInstagram: https://tinyurl.com/35cu4kr4Acknowledgments and sponsorsThis episode was supported by the National Centre of Competence in Research on «Dependable, ubiquitous automation» and the IFAC Activity fund. The podcast benefits from the help of an incredibly talented and passionate team. Special thanks to L. Seward, E. Cahard, F. Banis, F. Dörfler, J. Lygeros, ETH studio and mirrorlake . Music was composed by A New Element.